SkyChart is a software to draw chart of the night sky for the amateur astronomer from a bunch of stars and nebulae catalogs. See main web page for full download.
This software is part of a full suite for astronomical observation:
https://sourceforge.net/projects/ccdciel/
https://sourceforge.net/projects/indistarter/
https://sourceforge.net/projects/eqmodgui/
See also:
https://sourceforge.net/projects/indi/

The Pure Data (short Pd) project on SourceForge unifies the extensions (or externals) written for the Pure Data Graphical Computer Music System written by Miller Puckette with contributions from many others.

Lazarus is a free and open source development tool for the Free Pascal Compiler. The purpose of this project is to serve as a Code Repository, Wiki Knowledgebase and support site for converting existing components and libraries to work with Lazarus and the Free Pascal Compiler.

Fast C++ matrix library with easy to use functions and syntax, deliberately similar to Matlab. Uses template meta-programming techniques.
Also provides efficient wrappers for LAPACK, BLAS and ATLAS libraries, including high-performance versions such as Intel MKL, AMD ACML and OpenBLAS.
For more details, see http://arma.sourceforge.net